Transcript Lower Extremity Arterial System

TBI or not TBI
The Question for Vascular labs
with Diabetic patients
Liz Lawrence, RDMS, RDCS, RVT
1
TBI or not TBI: that is the question. Is
it better to measure toe pressure
than ankle pressure in diabetic
patients?
Brooks B, Dean R, Patel S, Wu B, Molyneaux L,Yue DK.
Diabet Med. 2001 Jul;18(7):528-32
2
ANKLE BRACHIAL INDEX
REQUIREMENT IS BLOOD PRESSURE CUFF AND DOPPLER PROBE
3
DIAGNOSTIC CRITERIA FOR
ABI
Table 1.
Interpretation Of Ankle-Brachial Pressure Index (ABI) Worksheet
Clinical Presentation
Ankle-Brachial Index
Normal
> 0.95
Claudication
0.50-0.95
Rest pain
0.21-0.49
Tissue loss
< 0.21
This is the typical chart for categorizing arterial
disease based on the ankle brachial index.
Note that ‘normal’ is a value greater than .95
4
DIABETIC ARTERIES
Media calcifications
ABI VALUES > 1.3
5
P P G
 Photo
 Pleths  moGraphy
6
Expensive Physiological
Testing Equipment
New Affordable TBI equipment
Blood Pressure of the Toe is an alternative to ABI
7
Toe Brachial Index
for reliable data
Diagnostic Criteria for TBI
Range
Interpretation
 >0.7
Normal
 0.5-0.7
Mild
 0.35-0.5
Moderate
 <0.35 toe pressure 40 mmHg Moderate-Severe
 <0.35 toe pressure < 30 mmHg
Severe

From the Mayo Clinic Vascular Lab
8
ARTICLE REVIEWED
TBI or not TBI: that is the question.
Is it better to measure toe pressure than ankle
pressure in diabetic patients?
9
….agreement between the tests (ABI vs TBI)
when ABI is low or normal
ABI
TBI
.95-1.29
>.7
.50 – .94
.5 - .69
0.21-0.49
.35 - .49
10
Patients with ABI > 1.3
have ABI-TBI differences outside this range
ABI
TBI
>1.3
.35 -.95
11
Conclusion

In the majority of patients with diabetes,
assessment of TBI conveys no
advantage over ABI in determining
perfusion pressure of the lower limbs.
Only in those patients with overt
calcification, which gives an ABI > or =
1.3, are toe pressure measurements
superior.
12
The association between elevated ankle systolic pressures
and peripheral occlusive arterial disease
in diabetic and nondiabetic subjects.
Aboyans V, Ho E, Denenberg JO,
Ho LA, Natarajan L, Criqui MH.
J Vasc Surg. 2008 Nov;48(5):1197-203.
Diabetes is the dominant risk factor for a high
(> or =1.40) ABI. Occlusive PAD is highly
prevalent in subjects with high ABI, and these
subjects should be considered as PAD-equivalent.
13
Use and utility of ankle brachial index
in patients with diabetes.
Potier L, Abi Khalil C, Mohammedi K, Roussel R.
Eur J Vasc Endovasc Surg. 2011 Jan;41(1):110-6.
….Therefore, ABI thresholds of
less than 0.9 and more than 1.3
are highly suspicious for PAD and
high CV risk in diabetic patients.
14
CONSIDERATIONS
TBI is most reliable for monitoring patients
with Diabetes
 If TBI is not available, any patient with
increased ABI > 1.3 should be suspected of
having PAD
 Duplex Arterial Scanning can help with
identifying PAD in Diabetics with increased
ABI

15